Armstrong Whitworth Aircraft started on the A.W.27 Ensign in 1934 after receipt of a specification from Imperial Airways. The first aircraft was ordered in September of that year, with delivery expected in 1936; eleven more were ordered in May 1935. An order for a further two aircraft in 1937 brought the total to 14.

Production of their Whitley heavy bomber for the Royal Air Force was a priority, and work on the Ensign proceeded slowly. Construction took place not at the main Coventry factory, but at the workshops of Air Service Training Ltd in Hamble. Constant changes were requested by Imperial, slowing production further. As a result, the Ensign's maiden flight did not take place until 24 January 1938. Despite being underpowered, the aircraft was certified, and full airline service began between Croydon and Paris, France in October of that year.

Operational history: Three more Ensigns were completed by Christmas, 1938, and were dispatched with the holiday mail to Australia. All three suffered mechanical problems and did not reach their destination; all Ensigns were removed from active airline service and returned to Armstrong for improvements. Reliability was improved, and more powerful Armstrong Siddeley Tiger IXC engines aided performance somewhat.

Eleven aircraft were in service at the outbreak of World War II, with a twelfth following soon after, and all were withdrawn in October, 1939 to be camouflaged before flying a new route from Heston and Le Bourget Airport in Paris. The aircraft remained in service after formation of BOAC that November. Three Ensigns were destroyed or captured due to Enemy action in 1940 , with one ("Ettrick"), which had been abandoned at Le Bourget after being damaged by bombs, eventually being used by the Germans, being re-engined with Daimler-Benz engines.

The final two aircraft that had been ordered by Imperial were equipped with more powerful Wright Cyclone geared radial engines and completed as A.W.27A Ensign Mk. 2s. The new engines significantly improved performance and allowed the Ensign to be used in hot climates and at high altitude. All eight surviving airframes were upgraded with these newer engines in 41-43 and worked for BOAC on Africa to India routes.

Ensigns flew throughout the war. One ("Enterprise") force-landed in West African Vichy territory and served the Vichy forces and Air France, subsequently ending up with the Luftwaffe after being re-engined like "Ettrick". Several were broken up for spare parts to support the remaining fleet. The final Ensign flight took place in 1946, and the last seven aircraft were scrapped in 1947.

Variants: A.W.27 Ensign I Four-engine medium-range transport aircraft. Powered by four 850-hp (634-kW) Armstrong Siddeley Tiger IXC radial piston engines. A.W.27A Ensign II Four-engine medium-range transport aircraft. Powered by four 950-hp (708-kW) Wright GR-1820-G102A Cyclone radial piston engines.

General characteristics: Crew: 5: captain, first officer, radio operator, two cabin stewards Capacity:

European routes: 40 passengers in 4 cabins Asian routes: 27 passengers in 3 cabins Length: 114 ft 0 in (34.8 m) Wingspan: 123 ft 0 in (37.5 m) Height: 23 ft 0 in (7.02 m) Wing area: 2,450 ft² (227.6 m²) Empty weight: 35,075 lb (15,900 kg) Loaded weight: 55,500 lb (25,200 kg) Useful load: 12,000 lb (5,450 kg) Powerplant: 4× Wright GR-1820-G102A geared radial engines, 1,100 hp (820 kW) each Performance Maximum speed: 210 mph (180 knots, 330 km/h) Cruise speed: 180 mph (160 knots, 290 km/h) Range: 1,370 mi (1,190 nm, 2,200 km) at 5,000 ft (1,500 m) Service ceiling: 24,000 ft (7,300 m) when fully loaded Rate of climb: 900 ft/min (4.57 m/s) Wing loading: 22.6 lb/ft² (110 kg/m²)